Valve assembly with overstroke device and associated method

ABSTRACT

A valve assembly comprises a rotatable valve, an electrically operated actuator, and an overstroke device. The actuator comprises a component configured to move in a direction to an actuator position so as to cause corresponding rotation of the valve to a valve position in response to electrical operation of the actuator. The overstroke device is configured to enable the component to move in the direction beyond the actuator position to an overstroke position while the valve remains in the valve position in response to electrical operation of the actuator. An associated method is disclosed.

FIELD OF THE DISCLOSURE

The present disclosure relates to a valve assembly and method which areparticularly useful in engine exhaust system applications.

BACKGROUND OF THE DISCLOSURE

Valves are used for many purposes. For example, valves have been used inengine exhaust system applications for flow control and acousticalreasons, to name just a few.

SUMMARY OF THE DISCLOSURE

According to an aspect of the present disclosure, there is provided avalve assembly. The valve assembly comprises a rotatable valve, anelectrically operated actuator, and an overstroke device. The actuatorcomprises a component configured to move in a direction to an actuatorposition so as to cause corresponding rotation of the valve to a valveposition in response to electrical operation of the actuator. Theoverstroke device is configured to enable the component to move in thedirection beyond the actuator position to an overstroke position whilethe valve remains in the valve position in response to electricaloperation of the actuator. By allowing the component to overstroke inthis way, the electrical current draw by the actuator can be reduced,thereby saving on power consumption and enhancing the useful life of theactuator. An associated method is disclosed.

The valve assembly and method are particularly useful in engine exhaustsystem applications. They are believed to be useful in otherapplications as well.

The above and other features of the present disclosure will becomeapparent from the following description and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a valve assembly with a closedflapper;

FIG. 2 is a sectional view showing a solenoid device of the valveassembly in a configuration corresponding to the closed arrangement ofFIG. 1;

FIG. 3 is an exploded perspective view showing components of the valveassembly;

FIG. 4 is a perspective view showing the valve assembly with an openflapper;

FIG. 5 is a sectional view showing the solenoid device in aconfiguration corresponding to the open arrangement of FIG. 4;

FIG. 6 is a perspective view showing the valve assembly with anoverstroked actuator;

FIG. 7 is a sectional view showing the solenoid device overstroked;

FIG. 8 is a simplified block diagram showing use of the valve assemblyin a cylinder deactivation scheme; and

FIG. 9 is a simplified block diagram showing use of the valve assemblyin an exhaust gas recirculation scheme.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the disclosure to the particular formsdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives following within the spiritand scope of the invention as defined by the appended claims.

In FIG. 1, there is shown a valve assembly 10. The valve assembly 10comprises a rotatable valve 12, an electrically operated actuator 14,and an overstroke device 16. The actuator 14 comprises a component 18configured to move in a direction 22 to an actuator position so as tocause corresponding rotation of the valve 12 to a valve position inresponse to electrical operation of the actuator 14 (see FIG. 4). Theoverstroke device 16 is configured to enable the component 18 to move inthe direction 22 beyond the actuator position to an overstroke positionwhile the valve 12 remains in the valve position in response toelectrical operation of the actuator 14 (see FIG. 6). By allowing thecomponent 18 to overstroke in this way, the electrical current draw bythe actuator 14 can be reduced, thereby saving on power consumption andenhancing the useful life of the actuator 14.

The valve 12 is rotatable between a closed position shown in FIG. 1 andan opened position shown in FIGS. 4 and 6. Rotation of a shaft 24 aboutan axis 25 (see FIG. 3) causes a flapper 26 secured thereto andpositioned in a passageway 28 (e.g., exhaust gas passageway in exhaustapplications) of a body 30 to rotate with the shaft 24 about the axis 25through an angle (e.g., about 60°) between the closed and openedpositions. The valve 12 is biased normally toward the closed position bya torsion spring 32 that acts through the actuator 14 and the overstrokedevice 16, as discussed in more detail below. Contact between theflapper 26 and a valve stop 34 establishes the valve 12 in the openedposition. It is contemplated that the valve 12 may be biased normallytoward the opened position.

The actuator 14 is operated by electrical power provided by anelectrical power source (not shown). The actuator 14 may include, but isnot limited to, a linear solenoid device, a rotary solenoid device,and/or a geared DC motor, to name just a few. By way of example, theactuator 14 is discussed and illustrated herein as having a linearsolenoid device 34. In such an exemplary case, a plunger of the linearsolenoid device 34 acts as the component 18 of the actuator 14, althoughit is to be understood that such a plunger is but one non-limitingexample of the component.

As shown in FIG. 2, the component 18 of the linear solenoid device 34 ismounted in a housing 38 for linear movement therein. Normally, thecomponent 18 is biased by a spring 40 to a first position against a stop42. The component 18 is positioned within an electrically conductingcoil 44 which is configured to cause the component 18 to move toward anactuator stop 20 when the coil 44 is energized.

Referring back to FIG. 1, a flexible line 48 (e.g., a cable) of theactuator 14 contained in a sheath secured to a mounting plate 46interconnects the component 18 and a pulley 50 of the actuator 14. Theline 48 is secured to the pulley by use of a lug 80 swaged to orotherwise secured to an end portion of the line 48. The pulley 50surrounds and is rotatable relative to the shaft 24 and rests on thespring 32. A first end portion 52 of the spring 32 presses against themounting plate 46 and a second end portion 54 of the spring 32 pressesagainst an arm 56 of the pulley 50 to bias the pulley 50 to the positionshown in FIG. 1.

The overstroke device 16 is configured, for example, as a torsion springinterconnecting the pulley 50 and the shaft 24. A first end portion 58of the device 16 is secured to the pulley 50 by receipt of the endportion 58 in an aperture 60 (see FIG. 3). A second end portion 58 ofthe device 16 is secured to the shaft 24 by receipt of the end portion58 in a slot 62 formed in an end portion of the shaft 24 surrounded bythe device 16. As such, the pulley 50 is secured to and positionedbetween the device 16 and the spring 32.

The overstroke device 16 is more stiff than the spring 32. In the casewhere the device 16 is a torsion spring, this means that its springconstant is greater than the spring constant of the spring 32, thepurpose of which is discussed in more detail below.

Referring to FIGS. 4 and 5, when the coil 44 is electrically energized,the component 18 is caused to move in the direction 22 along a path awayfrom the stop 42 toward the stop 20. Such motion causes the flapper 26to rotate away from its closed position toward its opened position. Assuch, the path of the component 18 has a valve actuation zone foractuating the valve 12. The valve actuation zone is defined between afirst end actuator position in which the component contacts the stop 42,as shown in FIG. 2, to an intermediate actuator position shown in FIG.5. When the component 18 reaches the intermediate actuator position, theflapper 26 is caused to make initial contact with the valve stop 34. Inthe valve actuation zone, the component 18 acts through the line 48, thepulley 50, the overstroke device 16, and the shaft 24 to rotate theflapper 26.

Further, in the valve actuation zone, the spring 32 is loaded due torotation of the pulley 50 but the overstroke device 16 is not loaded.This is because the overstroke device 16 is more stiff than the spring32. As such, in the valve actuation zone, the end portions 58 and 62 ofthe overstroke device 16 do not move relative to one another so thatrotation of the pulley 50 causes corresponding rotation of the shaft 24and flapper 26.

Referring to FIGS. 6 and 7, when the flapper 26 contacts the valve stop34, the shaft 24 and flapper 26 are blocked from further rotation withthe pulley 50. In other words, as the component 18 continues to move inthe direction 22 beyond the intermediate actuator position toward thestop 20 due to energization of the coil 44, the shaft 24 and flapper 26are unable to rotate. Indeed, the overstroke device 16 enables thecomponent 18 to move in the direction 22 beyond the intermediateactuator position to the overstroke position (located between theintermediate actuator position and a second end actuator positioncontacting the stop 20) while the shaft 24 and the flapper 26 remain inthe valve position established by the valve stop 34. The overstrokedevice 16 does so by allowing itself to be deformed and thus loaded dueto rotation of the pulley 50 relative to the shaft 24. Such deformityoccurs upon movement of the end portion 58 relative to the end portion62. The path of the component 18 thus has an overstroke zone definedbetween the intermediate actuator position and the second end actuatorposition.

When the component 18 reaches the overstroke position, electricalcurrent draw by the solenoid device 34 can be reduced. This may beachieved in a variety of ways depending on the type of solenoid device34 used. For example, the stop 20 may include an electrical switch 70 tobe actuated (e.g., closed) by the component 18 when the component 18reaches the overstroke position which, in this example, is the secondend actuator position. The solenoid device 34 may be configured suchthat actuation of the switch 70 causes electrical current draw by thesolenoid device 34 to be reduced to some non-zero value. Exemplarily,the coil 44 may be a single coil or comprise two coils (as suggested bythe horizontal dashed line through the coil 44), a pull coil and a holdcoil. In the case of two coils, the pull coil may be used to move thecomponent 18 to actuate the switch 70 causing the hold coil to take overto hold the component 18 in the overstroke position with a lowerelectrical current than needed by the pull coil. In another example, theswitch 70 may be eliminated in which case the hold coil may take overfrom the pull coil to hold the component 18 in the overstroke position(which may be spaced apart from the stop 20) upon elapse of apredetermined period of time in the overstroke position, allowingreduction of the electrical current draw. The device 34 is thus able toreduce its draw of electrical current (e.g., a reduction of about 97.5%)when the component 18 assumes the overstroke position, thereby saving onpower consumption and enhancing the useful life of the device 34.

When the coil 44 is de-energized (i.e., no electrical current suppliedto the coil 44), the components of the valve assembly 10 return to theiroriginal state shown in FIGS. 1 and 2. In particular, the spring 40moves the component 18 in a direction opposite to direction 22 away fromthe stop 20 toward the stop 42 back to the first actuator end position.The spring 32 is then able to act through the pulley 50, the overstrokedevice 16, and the shaft 24 to rotate the flapper 26 away from the valvestop 34 to the closed position.

The solenoid device 34 may take a variety of forms. For example, thesolenoid device 34 may be embodied as any solenoid device of theELECTROFORCE™ 1500 Series, 1750 Series, or 2000 Series available fromWoodward Governor Company located in Niles, IL.

The valve assembly 10 may be used in a variety of applications such asengine exhaust system applications. Two such applications are shown inFIGS. 8 and 9.

Referring to FIG. 8, the valve assembly 10 may be used in a cylinderdeactivation scheme. In such a scheme, a cylinder deactivation unit 66electrically coupled to an engine 68 via an electrical line 70 sendselectrical signals over an electrical line 71 to the valve assembly 10to move the valve 12 to a selected position in response to activation ordeactivation of a number of cylinders of the engine 68. Such adjustmentof the valve 12 controls flow of exhaust gas through a silencer 72(e.g., muffler, resonator) in order to achieve a desired sound qualityoutput when the engine 68 is operating in different modes havingdifferent numbers of operational engine cylinders. Use of the valveassembly 10 in the cylinder deactivation scheme would promote reductionof the overall power requirements of the scheme.

Referring to FIG. 9, the valve assembly 10 may be used in an exhaust gasrecirculation (EGR) scheme. In such a scheme, the valve assembly 10 mayfunction as an EGR valve under the control of a controller 74 via anelectrical line 76 to control recirculation of exhaust gas to the engine68. Use of the valve assembly 10 in the EGR scheme would promotereduction of the power requirements of the scheme.

While the concepts of the present disclosure have been illustrated anddescribed in detail in the drawings and foregoing description, suchillustration and description is to be considered as exemplary and notrestrictive in character, it being understood that only illustrativeembodiments have been shown and described and that all changes andmodifications that come within the spirit of the disclosure are desiredto be protected.

There are a plurality of advantages of the concepts of the presentdisclosure arising from the various features of the systems describedherein. It will be noted that alternative embodiments of each of thesystems of the present disclosure may not include all of the featuresdescribed yet still benefit from at least some of the advantages of suchfeatures. Those of ordinary skill in the art may readily devise theirown implementations of a system that incorporate one or more of thefeatures of the present disclosure and fall within the spirit and scopeof the invention as defined by the appended claims.

1. A method of operating a valve assembly, comprising the steps of:electrically operating an actuator so as to move a component of theactuator in a direction to an actuator position to cause correspondingrotation of a valve to a valve position, electrically operating theactuator so as to move the component beyond the actuator position in thedirection to an overstroke position while the valve remains in the valveposition, and reducing electrical current draw by the actuator as aresult of the component assuming the overstroke position.
 2. The methodof claim 1, wherein the second operating step comprises loading atorsion spring interconnecting the actuator and the valve.
 3. The methodof claim 2, wherein: the torsion spring interconnects a pulley and ashaft secured to a flapper of the valve, and the loading step comprisesrotating the pulley relative to the shaft.
 4. The method of claim 2,wherein the first operating step comprises not loading the torsionspring.
 5. The method of claim 1, wherein: the component comprises aplunger of a linear solenoid device, the first operating step comprisesmoving the plunger to the actuator position so as to rotate a flapper ofthe valve into contact with a valve stop, and the second operating stepcomprises moving the plunger from the actuator position to theoverstroke position while the flapper remains in contact with the valvestop.
 6. The method of claim 1, further comprising controlling flow ofexhaust gas of an engine as a result of the first operating step.
 7. Avalve assembly, comprising: a rotatable valve, an electrically operatedactuator comprising a component configured to move in a direction to anactuator position so as to cause corresponding rotation of the valve toa valve position in response to electrical operation of the actuator,and an overstroke device configured to enable the component to move inthe direction beyond the actuator position to an overstroke positionwhile the valve remains in the valve position in response to electricaloperation of the actuator.
 8. The valve assembly of claim 7, wherein thevalve is positioned in an exhaust gas passageway associated with anengine.
 9. The valve assembly of claim 7, wherein the overstroke devicecomprises a first spring interconnecting the valve and the actuator. 10.The valve assembly of claim 9, wherein the first spring is a firsttorsion spring.
 11. The valve assembly of claim 10, wherein: the valvecomprises a rotatable shaft, the actuator comprises a pulley, and thetorsion spring interconnects the shaft and the pulley.
 12. The valveassembly of claim 11, wherein the torsion spring comprises a first endportion secured to the shaft and a second end portion secured to thepulley.
 13. The valve assembly of claim 10, further comprising a secondtorsion spring biasing the valve away from the valve position, whereinthe first torsion spring is more stiff than the second torsion spring.14. The valve assembly of claim 7, wherein the actuator reduces its drawof electrical current as a result of the component assuming theoverstroke position.
 15. The valve assembly of claim 7, wherein: theoverstroke device interconnects the actuator and the valve, and thecomponent is configured to move along a path comprising a valveactuation zone in which the component acts through the overstroke deviceto rotate the valve and an overstroke zone in which the overstrokedevice enables the component to move to the overstroke position whilethe valve remains in the valve position.
 16. The valve assembly of claim15, wherein: the valve comprises a rotatable flapper and a rotatableshaft secured to the flapper to rotate the flapper into contact with avalve stop to establish the valve in the valve position, the componentcomprises a plunger configured to move along a linear path comprisingthe valve actuation zone and the overstroke zone, the actuator comprisesa pulley secured to the plunger for movement therewith, the overstrokedevice comprises a torsion spring interconnecting the pulley and theshaft, and the torsion spring transmits motion of the plunger intorotation of the shaft during movement of the plunger in the valveactuation zone but does not transmit motion of the plunger into rotationof the shaft during movement of the plunger in the overstroke zone. 17.A valve assembly, comprising: a rotatable valve, a valve stop, asolenoid device, a rotatable pulley secured to the solenoid device, anda first torsion spring interconnecting the pulley and the valve to allowrotation of the pulley relative to the valve during contact between thevalve and the valve stop and energization of the solenoid device. 18.The valve assembly of claim 17, wherein: the valve comprises a rotatableflapper and a rotatable shaft secured to the flapper, and the firsttorsion spring interconnects the pulley and the shaft to allow rotationof the pulley relative to the shaft during contact between the valve andthe valve stop and energization of the solenoid device.
 19. The valveassembly of claim 17, wherein: the solenoid device comprises a plunger,and the first torsion spring allows the plunger to move to an overstrokeposition after the valve contacts the valve stop during energization ofthe solenoid device.
 20. The valve assembly of claim 17, furthercomprising a second torsion spring, wherein: the second torsion springacts through the pulley and the first torsion spring to bias the valveaway from the valve stop, and the first torsion spring is more stiffthan the second torsion spring.